VulnerabilityPublished 9 Oct 2025

CVE-2025-59980: Juniper Networks Junos OS · Authentication Bypass by Primary Weakness

Affects Juniper Networks Junos OSSource CVE Database V5

Not known to be exploited · CVSS 6.5 Medium.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score

6.5Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.2% chance of exploitation in 30 days – higher than 21% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: Low
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 9 Oct 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Juniper Networks Junos OS	Affected =0 =23.2 =23.4	Fixed in–

AI-suggested

European organizations should immediately audit their Junos OS devices to identify versions affected by this vulnerability and verify if the FTP server is enabled along with the presence of 'ftp' or 'anonymous' user accounts. If FTP is not required, it should be disabled entirely to eliminate the attack surface. Where FTP is necessary, restrict access to trusted management networks and consider using more secure file transfer methods such as SFTP or SCP. Monitor device logs for any unauthorized FTP login attempts. Implement network segmentation and access controls to limit exposure of management interfaces. Stay informed on Juniper's official patches and apply updates promptly once released. Additionally, review and harden user account configurations to remove or disable default or anonymous accounts. Employ intrusion detection systems to alert on anomalous FTP activity. Finally, conduct regular security assessments and penetration tests focusing on network infrastructure devices to detect similar weaknesses proactively.

Description

CVE-2025-59980 is an authentication bypass vulnerability in the FTP server component of Juniper Networks Junos OS. It allows an unauthenticated attacker to log in as the 'ftp' or 'anonymous' user without a password, gaining limited read-write access to the user's home directory. This affects all Junos OS versions prior to 22.4R3-S8, 23.2 versions before 23.2R2-S3, and 23.4 versions before 23.4R2. The vulnerability requires the FTP server to be enabled and the presence of the 'ftp' or 'anonymous' user account. The CVSS score is 6.

Impact

For European organizations, this vulnerability presents a risk of unauthorized access to critical network infrastructure devices running Junos OS with FTP enabled. Attackers could leverage this flaw to read sensitive configuration files or logs, potentially gaining insights into network topology or credentials. Limited write access could allow modification of files within the home directory, which might be leveraged for persistence or to disrupt device operation indirectly. Given Juniper's strong market presence in Europe, especially among telecom providers, ISPs, and large enterprises, exploitation could lead to data breaches, network disruptions, or facilitate further lateral movement within corporate networks. The lack of required authentication and user interaction lowers the barrier for attackers, increasing the likelihood of exploitation in poorly secured environments. While availability is not directly affected, the confidentiality and integrity impacts could have cascading effects on network security and compliance with European data protection regulations such as GDPR.

CWE-305Authentication Bypass by Primary Weakness (opens in a new tab)
Base weaknessOWASP Top 10 A07:2025: Authentication Failures (opens in a new tab)
The authentication algorithm is sound, but the implemented mechanism can be bypassed as the result of a separate weakness that is primary to the authentication error.
OWASP Cheat Sheets
OWASP Authentication (opens in a new tab)
OWASP ASVS 4.0.3
V2.8.5 (opens in a new tab)
V2.8.4 (opens in a new tab)
V9.2.3 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

supportportal.juniper.net/JSA103167 (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 17 Oct 2025, 05:22 UTC

WeaknessesCWE-305

Technical details

References

Community reviews

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